Five of the Most Common Autoimmune Diseases, Explained

When foreign invaders such as bacteria and viruses infect you, your immune system kicks into gear to fight those pathogens. But unfortunately, not everyone's immune system sticks to just fighting the bad guys. For those with autoimmune disorders, the immune system mistakenly starts attacking its own parts as foreign invaders. As a result, you might start experiencing symptoms that range from joint pain and nausea to body aches and digestive discomfort.

Here, what you need to know about the signs and symptoms of some of the most common autoimmune diseases so you can keep an eye out for these uncomfortable attacks.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that typically causes inflammation of the joints and the encompassing tissue, according to the Centers for Disease Control and Prevention (CDC). It can also affect other parts of the body, such as the lungs and heart. The disease can appear at any age, although cases of RA are 2 to 3 times more likely in cisgender women, per the CDC. Other factors such as a history of smoking, obesity, or your genes can increase your risk of developing RA. However, a history of breastfeeding can actually lower your risk.

Be on the lookout for symptoms such as prolonged joint pain and/or morning stiffness, fatigue, low-grade fever, weakness, and loss of appetite. When considering your joint pain, note if there's discomfort in more than one joint and whether the same joints on both sides of the body are affected, notes the Arthritis Foundation, which also points out that smaller joints are typically the first to develop the pain.

Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease in which the immune system incorrectly attacks healthy tissues in the central nervous system. The central nervous system is made up of the brain and the spinal cord and is responsible for, among other things, "receiving, processing, and responding to sensory information," per the National Institute of Health. Over time, MS causes gradual damage to the central nervous system that interferes with the transmission of nerve signals between the brain and spinal cord, and other parts of the body, according to the National Multiple Sclerosis Society.

Symptoms can vary from person to person and might include fatigue, dizziness, involuntary muscle spasms, double or blurry vision, depression, and memory issues. The disease is more prevalent among 20- to 40-year-olds, although it can occur at any age. Cisgender women are more likely to be affected by MS than cisgender men, and environmental factors such as low vitamin D and a history of smoking can increase the risk.

Fibromyalgia

This chronic condition is distinguished by widespread body pain in your muscles and joints, and people who suffer from it are more sensitive to pain, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Cisgender women are twice as likely to have fibromyalgia than cisgender men, and you're at a higher risk of developing the condition if you have lupus of RA.

Commonly, defined tender points in the joints, muscles, and tendons that cause burning and stabbing pain have been linked with fibromyalgia, according to the Arthritis Foundation. Other symptoms include fatigue, inability to sleep, memory difficulties, migraines, numbness, and depression, per the CDC. Fibromyalgia might also cause irritable bowel symptoms, so it's quite possible for patients to experience both joint pain and nausea.

Celiac Disease

Celiac disease is a digestive condition in which consuming the protein gluten damages the lining of the small intestine. Gluten is found in all forms of wheat and related grains rye, barley, and triticale, according to the U.S. National Library of Medicine (NLM). Celiac disease is genetically inherited — however, it can develop at any age. Unfortunately, the older you are when the condition develops, the more likely it is that you'll develop another autoimmune disorder.

Celiac disease is often hard to diagnose because it affects people differently, and also because its symptoms are similar to other potential issues, according to the Celiac Disease Foundation. Symptoms vary and can include abdominal pain, constipation or diarrhea, unexplained weight loss, missed periods, depression, weakness, or lack of energy. On top of that, patients with celiac disease might also experience joint pain and nausea.

Ulcerative Colitis

The inflammatory bowel disease called ulcerative colitis primarily affects the large intestine and rectum and is characterized by abdominal pain and diarrhea, according to the NLM. Other symptoms include weight loss, loss of appetite, fever, gastrointestinal bleeding, and nausea. The disorder affects about 750,000 people in North America, and it's not completely understood why, exactly, people develop the disease, adds the NLM.